// The standard header file <sstream> defines a class called stringstrea
// that allows a string-based object to be treated as a stream.
// This way we can perform extraction or insertion operations from/to strings,
// which is especially useful to convert strings to numerical values and vice versa.
// For example, if we want to extract an integer from a string we can write:
string mystr ("1204");
int myint;
stringstream(mystr) >> myint;